The Value of Soil Analyses to the Farmer. 7 



always arising from the decay of vegetable matter. Heavy 

 land needs carbonate of lime to keep the clay granular and 

 enable the soil to crumble, to drain and dry, and so get warm ; 

 light land loses its carbonate of lime most quickly by washing 

 and readily gets acid. As soon as the soil passes the neutral 

 point a great disturbance sets in among the bacteria and other 

 small organisms which have to prepare the food for plants, 

 certain valuable forms are discouraged and may die out, those 

 for example which fix nitrogen and those which cause nitrific- 

 ation. In their place micro-fungi can flourish, some of which 

 cause disease, as for example the fungus of finger and toe, 

 which cannot persist in a soil kept neutral by the presence of 

 carbonate of lime. It is not too much to say that only soils 

 containing a sufficiency of carbonate of lime can be really 

 fertile or can make full use of the manure with which they 

 may be supplied. We now possess methods of analysis which 

 will measure the very small amounts of carbonate of lime 

 present in many soils, and again we are able to form better 

 estimates of soil acidity or otherwise than can be obtained from 

 the simple but misleading litmus paper. 



From these facts alone the soil analyst is in a position to 

 give certain advice to the farmer ; he can tell him whether to 

 lime or not, whether to use nitrate of soda or sulphate of 

 ammonia when he wants a quick acting nitrogenous fertiliser, 

 whether for his turnips superphosphate or basic slag should be 

 chosen or some neutral body like phosphatic guano or steamed 

 bone flour. Manures are themselves acid or basic in their 

 action on the soil, and they should be selected so as to neutralise 

 and not to intensify its natural condition. As an example of 

 the ease with which we may be deceived, on the black Fen soils 

 superphosphate is the most valuable of all manures, yet it is most 

 dangerous to use it on other black soils of a peaty nature ; the 

 Fen peat is neutral even alkaline, and neutralises the acid of 

 the superphosphate ; l)og and mocirland peats are acid. As to the 

 other constituents, the analyst can sometimes provide valuable 

 information with regard to the special need of the soil for phos- 

 phates and more rarely for potash. But this generally necessitates 

 some previous knowledge of the type of soil, for it is not bo 

 much the absolute amount of either constituent that is 

 significant as the amount relative to that which usually 

 prevails in soils belonging to that group. For example, lo find 

 0'16 per cent, of phosphoric acid in a given soil tells nothing, 

 but to find such a result in a Thanet Sand soil would mean that 

 the soil is well provided and needs no special phosphatic 

 manuring, whereas such a figure from a Chalk soil would 

 generally signify deficiency in phosphoric acid. Again we see 

 the necessity of soil surveys by which the general type of our 



